Why can't I save my configuration settings?

My MODx site seems every bit workable except when it comes to the configuration settings (Tools->Configuration).

When I press the save button, an Internal Server error page comes up every time. This does not happen for any other save button. Can anyone point me out to the exact cause of the problem, please? When hovering over the save and cancel button, both points to index.php?a=17

It would be difficult (time, e-mail, etc) if I cannot use the configuration settings properly. Thank you.
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I’m using 0.9.6

Odd.... are you using clean URLs in the frontend ?

If so (and only if so), did you rename the ht.access file in /manager/ into .htaccess to avoid manager files to be rewritten by Apache (assuming you run Apache) ?

Also, more info about your config wouldn’t hurt (PHP, MySQL and Apache version)

Thanks for your reply.

I am not using clean URLs though (we still see the ?id=123). But my site is in the testing phase, so there aren’t much of the clutter in the URL. Yes, I am on a server running Apache but I did not touch anything in the /manager folder (ht.access). I am totally new to MODx, having used Drupal, then Joomla (not intuitive), then Xoops (better and more configurable but very messy lately). I want to tread this CMF slowly because its huge but intuitive unlike Joomla.

So right now, I would like to listen to advice because I’m new

Apache 1.3.37
PHP 4.4.6
MySQL 4.1.21